You have two parallel lines, with a transversal. (Extent both vertical lines to confirm this, if you're not sure.)

So there is a twelve-degree angle to the bottom left of the second vertical. This tells you the size of the angle between the upper portion of the second vertical and the transversal. Subtracting, you can find the size of the rest of the angle currently labelled "102 deg" in your diagram. Since a straight line has an "angle" measure of 180°, you can find the size of the rest of the angle at the peak of the triangle.

Once you have this value, you should be able to see where to go from there....